Field
The present disclosure relates generally to systems for creating a durable seal between adjacent panels, including those which may be subject to temperature expansion and contraction or mechanical shear. More particularly, the present disclosure is directed to providing an integral multilayer joint seal system against one or more of water, fire, sound, air, smell, radiation, resistant and/or heat.
Description of the Related Art
Construction panels come in many different sizes and shapes and may be used for various purposes, including roadways, sideways, and pre-cast structures, particularly buildings. Use of precast concrete panels for interior and exterior walls, ceilings and floors, for example, has become more prevalent. As precast panels are often aligned in generally abutting relationship, forming a lateral gap or joint between adjacent panels to allow for independent movement, such in response to ambient temperature variations within standard operating ranges, building settling or shrinkage and seismic activity. Moreover, these joints are subject to damage over time. Most damage is from vandalism, wear, and environmental factors, where the seal may become thick and inflexible or are fragile. As a result, “long lasting” in the industry refers to a joint likely to be usable for a period greater than the typical lifespan of five (5) years. Various seals have been created in the field.
Various seal systems and configurations have been developed for imposition between these panels to provide seals which provide one or more of fire protection, waterproofing, and air insulation. This typically is accomplished with a seal created by imposition of multiple constituents in the joint, such as silicone application, backer bars, and compressible foams. Alternative prior art systems have included extruded glands and metallized bellows.
These systems, however, often fail due to the differences in compression and expansion of the various constituents, or the lack of bonding between layers, or because the system is directed to a particular purpose, such as water-resistance, but is exposed to fire, causing the seal system to fail and permit water to migrate behind the seal system. Vandalism, normal wear, and environmental exposure can change or defeat the properties of the exposed surface coating or membrane. There is also the case where the best material or barrier may not be used because it is aesthetically unpleasing or cannot easily be colored. By moving the membrane feature to an internal level sufficient to protect it and allow for the best properties of the joint sealant, these limitations can be overcome and the useful lifespan extended.
Additionally, in some cases the movement of the joint may be limited, sometimes to only twenty-five percent (+/−25%) in compression and expansion, for a total movement of only fifty percent (50%). These systems often use closed-cell, rather than open-cell, polyurethane foams. The need exists for a seismic joint having at least about fifty percent (50%) movement in each direction, for a movement total of about one hundred percent (100%) or more.
It would be an improvement to the art to provide a joint seal system which would include a plurality of compressible layers joined into a single unit prior to imposition and which would include a membrane barrier positioned intermediate two compressible layers. It would be a further improvement to provide the various compressible layers with differing functional properties, such as, for example, waterproofing and/or fire retardancy and durability associated with fire ratings.
Additionally, for pre-compressed joint sealants with a silicone face, a myriad of potential failure risks exists. Typically, the surface coating of these joints is relatively thin and can be damaged. Where joint substrate is irregular, a complete seal at the joint face might not be accomplished. Water intrusion from behind the joint face could find its way into or past the joint sealant and may result in poor performance or a leak, particularly problematic is products that rely on water-based intumescent surface coating, which can revert or delaminate if subject to continuous moisture. Pre-compressed or compressible joint sealants without an elastomer coating or surface impregnation often have similar limitations.
It would therefore be are improvement to safeguard the critical functions, by way of membrane barrier or the membrane barrier separating different operations of the foam, away from the surface where they can be damaged or bypassed. Thus, the joint seal surface will serve its primary aesthetic function of filling the joint with a matching or pleasing color without having the primary purpose of the system (water, fire etc.) subject to failure from superficial damage.
Additionally, foam sealants can take a compression set at some point. If the foam sealant systems designed based on laminations (acrylics or strong pressure sensitive adhesives in particular) are parallel to the joint substrate, they tend to separate over time, losing their sealant properties. The norm for these pressure sensitive adhesives impregnated systems is to use multiple, parallel laminations that are held together by their own adhesive force. These types of systems rely heavily on the elastomer surface coating for sealing and intumescent surface coatings for fire resistance. If there is any damage to the thin (60 mil or less coating) the system will not perform as designed. This is further complicated by the use of the multiple laminations that if separated would let water, smoke or fire penetrate system. Failure of any of these listed shortcomings will reduce the useful lifespan of the joint sealant.
Because the primary sealant is always subject to adhesive, cohesive, and environmental forces and therefore tends to wear out over time and leak, it is a good practice to have redundant systems.
Therefore, it would be an improvement to provide a joint seal with its own redundancy, particularly with regard to compression of foam seals.
Finally, it would be an improvement to provide a joint seal having a laminated or profiled lamination structure that could benefit from the push pull function of the joint.